The present invention relates to a device and method for evaluating magnetic resonance (MR) imaging machines. More particularly, the invention relates to a device and method for determining the gradient magnetic field and radio frequency (RF) pulses of an MR pulse sequence in an MR imaging machine.
The gradient magnetic field and RF pulse sequence of an MR imaging machine are unique for a given machine manufacturer, and even for given machine models made by a specific machine manufacturer. Therefore, proper evaluation of an MR imaging machine requires accurate determination of these pulse sequences.
Presently, the MR pulse sequences can be determined only by utilizing software-based predictions of pulse sequence parameters, or by measuring the signals directly using test equipment. Because the software only provides pulse sequence predictions, this method is not sufficiently accurate. Moreover, it requires special software and hardware interaction with the MR imaging machine under evaluation. Measuring the signals directly provides a fairly accurate method of determining the pulse sequence; however, this method also requires physically connecting external test equipment to the MR imaging machine under test. Since many MR imaging machines do not provide test ports designed for test equipment connection, these machines must be opened up to allow the equipment to be connected. Thus, this method presents potential hazards for both the MR imaging machine and testing personnel.
The present invention is a coil assembly having a plurality of magnetic field induction coils mounted to a frame along with a radio frequency (RF) detection coil and a processor which connects to these coils and samples their signals. The frame is positioned in the bore of an MRI system to detect the gradient magnetic fields and RF field produced during a scan, and the processor displays the gradient and RF field waveforms of the pulse sequence being performed by the MRI system. All three gradient waveforms can be displayed.